This invention relates to an apparatus for turning sheets over, and more particularly, to an improved sheet inverting inverter apparatus that combines a disc stacker with a vacuum transport.
Although, a sheet inverter is referred to in the copier/printer art as an "inverter", its function is not necessarily to immediately turn the sheet over (i.e., exchange one face for the other). Its function is to effectively reverse the sheet orientation in its direction of motion. That is, to reverse the lead and trail edge orientation of the sheet. Typically, in inverters as disclosed here, the sheet is driven or fed by feed rollers or other suitable sheet driving mechanisms into a sheet reversing chute. By then reversing the motion of the sheet within the chute and feeding it back out from the chute, the desired reversal of the leading and trailing edges of the sheet in the sheet path is accomplished. Depending on the location and orientation of the inverter in a particular sheet path, this may, or may not, also accomplish the inversion (turning over) of the sheet in some applications, for example, where the "inverter" is located at the corner of a 90.degree. to 180.degree. inherent bend in the copy sheet path, the inverter may be used to actually prevent inverting of a sheet at that point, i.e., to maintain the same side of the sheet face-up before and after this bend in the sheet path. On the other hand, if the entering and departing path of the sheet, to and from the inverter, is in substantially the same plane, the sheet will be inverted by the inverter. Thus, inverters have numerous applications in the handling of either original documents or copy sheets to either maintain, or change, the sheet orientation.
In the field of reprographic machines, it is often necessary to feed along one of two alternate paths a copy sheet leaving the processor of the machine, particularly when the machine can selectively produce simplex (one-sided) and duplex (two-sided) sheets. Simplex sheets may be fed directly to an output tray, whereas the duplex sheets may pass to a sheet feeder which automatically reverses the direction of movement of a simplex sheet and feed it back into the processor, but inverted, so that the appropriate data can be applied to the second side of the sheet. One known sheet-feeder (U.S. Pat. No. 4,359,217) for effecting this includes three rollers in frictional or geared contact with each other, to provide two spaced-apart nips, one being an input nip to an associated downstream sheet pocket, and the other being an output nip for extracting each sheet from the pocket. A reversal unit for a document copying apparatus is shown in U.S. Pat. No. 3,227,444 in which documents to be copied are placed on a feed table and individually fed from the table to a rotating drum. The documents moves through a recording station where the obverse side, i.e. the side away from the drum is recorded. After the document is discharged from the drum it is either directed to a receiving hopper or to a reversal unit that includes a reversibly driven belt conveyor. Documents received on the belt conveyor are subsequently driven off the belt conveyor with the trail edge of the documents becoming the leading edges.
The present invention aims at providing an inverter designed to have a sheet to be duplexed fed to it, stored momentarily, and fed back to a processor for imaging onto the opposite side. The inverter includes a transport mechanism that combines a disk stacker and a vacuum-belt transport which accommodates various size sheets and allows the same or different exit nip speeds.